Original 1957 GMC Truck Dealer Service Manual. This Maintenance Manual covers 100 thru 500 Model Trucks. These Manuals are what the Dealership used to service and repair your truck. It contains information, illustrations, diagrams, specifications and procedures to service your vehicle. Very informative and useful tool for the GMC owner. Good condition for its age with normal wear, blemishing and soiling from use in a Dealership [see photos].